The present invention relates to a video-data processor for displaying a video data in multiple windows on a screen of the personal computer or the like.
In view of the fact that a video signal is full of reality and has a motion easily understandable, there is a gradually rising demand for displaying it on the screen of a personal computer in a manner similar to characters and graphics. FIG. 36 is a block diagram showing a conventional video data processor for digitizing an analog video signal and displaying it in combination with graphics. In FIG. 36, reference numeral 3601 designates video-data A/D means for digitizing an analog video signal according to the NTSC or the like standard, numeral 3602 a graphic memory on which a graphic data is drawn, numeral 3603 a color-designating register having stored therein a given color of the graphic data on the graphic memory 3602, numeral 3604 video/graphic combination means for selecting a video-data output from the video-data A/D means 3601 when a pixel having the color stored in the color-designating register 3603 is produced among the graphics produced from the graphic memory 3602, and selecting a graphic output in the other cases thereby to combine the video-data graphics, and numeral 3605 display means for displaying a combined output from the video/graphic combination means.
If the data stored in the color-designating register of the video-data processor is changed, it is possible to produce such a special effect as to change the manner of combining a video data and a graphic.
In recent years, a multi-window screen has been closely watched as a screen for dialogue with the computer providing a better human-machine interface. The multi-window screen has a plurality of rectangular areas called the windows on a single display means in such a way as if each window is an independent display means.
If a video data is to be adapted to this multi-window screen, means are required for moving, handforming and redrawing the windows. Also, it is necessary to combine the video data with graphics and special effect compatibly on the multi-window screen.
In the conventional video-data processor shown in FIG. 36, however, the whole area of the video data cannot be moved independently of the display means 3605, and therefore it is impossible to adapt a video data to a multi-window screen, as seen from an example shown in FIG. 37. In FIG. 37a, numeral 3701 designates the whole video-data screen applied as an input. Numeral 3702 in FIG. 37b designates a display screen having one window displayed on the display means 3605. Numeral 3703 designates a window displaying a video data, which is realized by applying the color stored in the color-designating register 3603 to the whole area of the graphic memory 3602 corresponding to the window 3703. In FIG. 37c, numeral 3704 designates a screen of the display means which is required to be realized when the window 3703 is relocated down to the right. The window 3703 before relocation and the window 3705 after relocation must have the same content. Actually, however, as shown by the screen designated by 3706 in FIG. 37d, the content of the window 3707 after relocation is considerably different from that of the window 3703 before relocation.